Virtual movies are widely used for a variety of purposes, such as exhibitions, remote guidance and touring of places, education, training, electronic games, etc. Some of such movies are animated, and some others are real, in the sense of involving real frames that are photographed within a tangible site. The present invention relates to the latter case, i.e., to the case where the preparation of a virtual and interactive movie enables a user to explore a tangible site.
For example, there are some cases in which it is desired to allow a user to view a filmed representation of a site, and navigate interactively thereinafter within the site. More particularly, it is desired to produce an interactive movie enabling the user to view a desired region of a site in any selected direction, while viewing continuously changing actual images of the selected region that may be optionally combined with computer generated interactive or non-interactive events or objects.
In another, more particular example, it is desired to produce a virtual interactive movie for training personnel so that they may be familiarized with a specific site, while being provided with essential and comprehensive information concerning the site, such as its layout, its appearance, location of rooms and equipment therein. Moreover, it could be beneficial to integrate a simulated event, for example, a fire, into the movie so that the personnel may learn how to deal with some emergency procedures.
Such virtual interactive movies that enable people to navigate within a tangible site can also be used for marketing purposes, for example, allowing viewers to interactively explore sites such as real estate properties, hotels, etc.
The preparation of a virtual, interactive movie which enables navigation within a site is generally a very complicated task, and it involves a substantial effort, requiring professional and lengthy filming and editing. Also, the results are generally not so satisfactory, being far from providing to the user a real navigating and exploring feeling.
International Patent Publication No. WO2004/049263 filed on Nov. 24, 2003 by same applicant discloses a method and apparatus for producing a virtual movie for the purpose of exploring a tangible site. According to said application, a movable platform supports all the system components. The movable platform is moved within the site, while measuring the x,y coordinates and the orientation (angle), producing site nodes (as defined in said application), acquiring site images, up to 360° field of regard, and performing additional processing tasks including the processing and preparation of the final movie.
Such a movable platform, as described in WO2004/049263 can generally perform this task. However, there are some problems associated with operating such platform, as follows:                a. When the system acquires images from the rear of the platform, the operator has to hide from view of each of the cameras in order not to appear in the acquired images.        b. The platform, which supports all the system components, is heavy, and the operator has to apply a significant force in order to move the platform and operate the system within the site.        c. As the platform has to smoothly move along the site, which generally includes a narrow passageway, such as a door, or negotiate around an obstacle, this task becomes even more complicated.        d. Additionally, as in many cases in which the system has to be transported from one site to another, it is important to have a relatively light weight platform, which also has a small volume.        e. Moreover, the movable platform drifts as the supporting caster wheels return to a normal trailing position, following a change in direction, resulting in a bothersome wobbling sensation in the produced virtual movie.        
It is therefore an object of the present invention to provide a mobile device which supports apparatus for imaging a site to be displayed in an interactive virtual movie and which overcomes all the above drawbacks.
It is an additional object of the present invention to provide a mobile device which is of relatively small dimensions, of relatively light weight, and with good maneuverability.
It is an additional object of the present invention to provide an operator with means for conveniently directing the mobile device to a desired region of a site, and means for conveniently controlling the operation of the imaging apparatus.
It is yet an additional object of the present invention to provide the mobile device with means for preventing drifting thereof during advancement between regions of the site, to increase the quality of the interactive movie being produced.
Other objects and advantages of the invention will become apparent as the description proceeds.